The effect of length of storage and sodium benzoate on the nutritive value of reconstituted sorghum grain silages for dairy cows

Abstract

Twenty Holstein cows at 168 ± 87 d in milk (mean ± SD) were assigned to a 4 × 4 Latin square design with a 2 × 2 factorial arrangement to evaluate the effects of 2 storage lengths (30 or 90 d) and the presence of sodium benzoate (control or 0.2% as fed) on the nutritive value of reconstituted sorghum grain silages (RSGS). For each treatment, dry ground sorghum grain was rehydrated to 35% moisture and ensiled in 200-L plastic drums. The treatments were RSGS stored for 30 d without sodium benzoate ( 30CON), RSGS stored for 30 d with sodium benzoate (30 BEN), RSGS stored for 90 d without sodium benzoate (90 CON) and RSGS stored for 90 d with sodium benzoate (90 BEN). Diets contained 16.3% RSGS. Silages stored for 90 d had higher concentrations of 1,2-propanediol, soluble protein, and ammonia nitrogen than did those stored for 30 d. Sodium benzoate reduced ethanol and ethyl-ester formation. Silages stored for 90 d had higher starch (89.3 vs. 86.9%) and protein (57.1 vs. 54.0%) digestibility compared with silages stored for 30 d. The ruminal acetate-to-propionate ratio tended to be lower in RSGS stored for 90 d than in RSGS stored for 30 d (3.75 vs. 3.34). Milk yield increased from 30.0 kg/d in cows fed RSGS stored for 30 d to 31.2 kg/d in cows fed RSGS stored for 90 d, without a change in dry matter intake (23.5 kg/d on average). Hence, feed efficiency and milk N efficiency also had tendencies to increase in cows fed RSGS stored for 90 d. Sodium benzoate did not alter cow performance but slightly increased plasma glucose (65.2 vs. 63.6 mg/dL). In conclusion, increasing the storage period of RSGS from 30 to 90 d improved starch and protein digestibility, milk yield, and feed efficiency.

Effects of exogenous protease addition on fermentation and nutritive value of rehydrated corn and sorghum grains silages

“…The lower DM content at 90 days of fermentation compared to 60 days, except for the 0.3% dose of the enzyme (see Supplementary Fig. S6 ), was probably due to microbial activity during the fermentation process, which naturally promotes reductions in DM contents with advancing ensiling time, as verified by Carvalho et al 11 and Da Silva et al 3 on CG silages and Santos et al 13 on rehydrated SG silage.…”

“…Increased in situ starch digestibility of rehydrated corn grain silage was observed by Fernandes et al 12 after 120 days of fermentation, compared to corn at ensiling, with values of 92.0 and 72.0%, respectively. For rehydrated sorghum grains silage, Santos et al 13 observed that cows fed diets containing silages stored for 30 days had lower starch digestibility (86.9%) compared to cows fed diets with silages stored for 90 days (89.3%).…”